Fix inconsistent data usage cycle start time.

- change the detail adapter start time to be 4 weeks before end time,
even if it is earlier than history start time, to be consistent with
other places that the cycle period is shown.

Change-Id: I62846022a10597f9e8618907500613357a1f6551
Fixes: 121045978
Test: make RunSettingsLibRoboTests
2 files changed